Liquid-fuel pump



Dec. 14.1926. 1,610,957

l G. R. LAWRENCE LIQUID FUEL PUMP Filed May 21, 1923 5 Sheet`sshet- 1 Q N Ev w m n 11 OO I m INI/ENYjoR.

A TTORNEYS.

Dec.14,19zs.- 4 www? G. R. LAWRENCE LIQUID FUEL PUMP Filed May 21, 1923 5 ShezuevtsS/hee'f 2- 60 7 5 Y aq Y l INVENTOR. M M y,

BY Wg# A TT ORNEYS.

Dec. 14, 1926. 1,610,957

G. R. LAWRENCE LIQUID FUE:J PUMP Filed May- 21 192: 5 Sheets-sheet s f1 ||||||||wm|| HlmmllmIII 9 a@ ywe a WM A TTQRNEYS.

G. R. LAWRENCE LIQUID FUELI PUMP Dec. 14, 192e. 1,610,957r

` Filed May 21, 1923 5 sheetsLSheet 4 y INVENTOR.

ATTORNEYS.

G. R. LAWRENCE Dec. 14 192e.

LIQUID FUEL PUMP Filed 'May 21,

/A .7.1 ...MWNWMWIIdPMW//l/ Y um INVENTOR. WM l ATTORNEYS Patented Dec. 14, 1926.

UNITED STATES PATENT oFFlcE.

GEORGE RAYMOND LAWRENCE, OF CHICAGO, ILLINOIS, ASSIGNOR TO COMMON- WEALTH ENGINEERING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.-

LIQUID-FUEL PUMP.

Application filed May 21,

This invention relates to mechanism 0f the same general type as that described in applicants application for patent, Serial No. 369,392, filed March 29, 1922, but the present construction is of simpler design and involves several improvements.

The pump device herein illustrated is shown as having connections with a liquid fuel burner for heating purposes, but may with equal success and in substantially the saine manner, be applied for delivering a fuel mixture to an internal combustion engine. The main object of the inventiony is to provide for a delivery of liquid hydrocarbon and air, in proportions which will remain constant regardless of a change in the rate of delivery or consumption, while convenient means' provide for varying the rate of delivery. This object of the invention is accomplished by a pump operated under power at substantially a -fixed speed, and arranged to idly circulate whatever fuel and air is pumped in excess of that required by the burner. However, all air and fuel which is handled by the pump is ultimately delivered to the burner, but none of the air drawn into the pump is discharged to the atmosphere, nor is any subjected to a carbureting action more than once.

A. further object of the invention is to provide an improved liquid fuel and air pump, in which the gears employed for operating the air blower or compressor part of the pump, are utilized as a gear pump for the liquid fuel. Other objects of the invention are to provide improvements in details of construction, including an improved regulating device.

The objects of the invention may be accomplished by a construction such as illustrated in the drawings, in which:

Figure 1 is a side view of a complete pumping unit and an attached burner nozzle. It shows an oil intake conduit and an oil overow conduit broken away but which lead to an auxiliary fuel reservoir, not shown. y

Figure 2 is an end view of the mechanism shown in Figure l.

-Figure 3 is an end View of the motor driven pump'with the gear pump cover removed.

1923. Serial No. 640,487.

Figure 4 is a sectional plan view of the pump taken on the line 4 4 of Figure 3.

Figure 5 is a sectional elevation of the pump taken on the line 5-5 of Figure 4.

Figure 6 is a sectional elevation of the pump taken on the line 6-6 of Figure 3.

Figure 7 is a sectional elevation of the pump taken on the line 7-7 of Figure 3.

Figure 8 is a sectional detail showing the regulator valve of the pump.

Figure 9 is a sectional detail of a carbureting valve taken on the line 9--9 of Figure 5. Figure l0 shows a modification of the carbureting valve shown in Figure 9, whereby its position automatically changes to compensate` for variations in temperature.

Figure l1 illustrates the use of an electric heater for warming the fuel in cold weather. The invention makes use of a constant s eed motor driven pump of the Root b ower type. ,The gears for driving the impellers of the pump areemployed for pumping liquid fuel into the housing of the pump, and the impellers of the air compressor part of the pump serve to pump air through the housing. The air in passing through the Vhousing atomizes and picks up the fuel beis the maintenance of a `uniform pressure of the carbureted airl delivered to the burner by passing into recirculation through the compressor all air pumped in excess of that required by the burner.

Referring to the drawings, Figure 1 shows a frame l, upon which is supported an electric motor 2 having a flexible shaft connection 3 with the main shaft 4 of the pump, the housing of which is indicated by 5 in Figure l. The pump is arranged to draw liquid fuel through the conduit 6 and excess fuel overflows back to an auxiliary fuel suply tank through the conduit 7. Mildly c arureted air is delivered by the pump through the conduits 8 and 9 to a burner 10, while air more heavily charged with fuel passes from the pump to the burner through conduit 12. A design of burner such as is described in applicants copending application before referred to, may be employed in this connection. The pressure of the air delivered to the burner 10 is controlled by the screw 13, and is indicated by gage 14.

The pump is driven at a constant speedl and has a capacity suicient for the maximum requirements, and is, therefore, -nor mally pumping` fuel slightly in excess of the quantity delivered to the burner 10. This excess quantity of fuel is discharged through the overflow conduit 7 into the supply tank.

The pump mechanismwithin housing 5 comprises a pair of gears 4() and 41, Figure 7, these gears being respectively pinned to shafts 4 and 42. These shafts also respec` tively carry the impellers 43 and 44 of a Root blower, Figures 4 and 5. The fuel is drawn into the gear pump through conduit 6, and the opening 45, Figure 7, in the face plate 46 for the gears, and is discharged by the gears downwardly through the conduit 47, formed in housing 5, into a chamber 48 at the bottom of housing 5. The overflow conduit 7 communicat-es with chamber 48 through the threaded boss 49. Chamber 48 communicates with an intake air passage 50, Figure 9, through a port 51, controlled by a needle valve 52. The air in entering conduit 50, rst passes through a i'ilter 53 and restrictive port 15 before passing the port 51, where under reduced pressure, it picks up a charge of fuel. The continued circuit of the air is through conduit 54 into the compressor housing 55. The carbureted air is' discharged from housing 55 by the rotating impellers 43 and 44 through a port 56 into an air chamber 57 In this chamber the carbureted airis maintained at the desired pressureand discharges into conduits 8 and 12 through the outlets 16 and 17 ,at the top and bottom of pressure chamber 57.

The pressure in chamber 57 is controlled by a check-valve 58, Figure 8, inpassageway 63 and urged to its seat by a spring 59. The tension of this spring is regulated by the screw 60. When the pressure in chamber 57 is high enough to lift valve 58 'from its seat, some of the air in this chamber is returned to conduit 54, Figures 4 and 5, leading to the intake of the compressor through the port 61 and conduit 62, which communicates at its lower end with conduit 54. By means of the screw the maximum pressure in chamber 57 is provided for. At this maximum pressure the valve 58 is above its seat and some of the carbureted air is bypassed back to the intake of the compressor without again passing the fuel port 51. All

air which enters the device is caused to pass the port 51 but once, and none of it is discharged back into the atmosphere, regardless of the rate of rotation of the pump. The proportion of air and fuel delivered toy the burner is constant, although its pressure and rate of delivery may be varied within wide limits byadjustment of screw 60, Figure 8.

Figure 11' shows the oil chamber 48 provided with a'n electric heating element 64, which may be under thermostatic control, and thus maintain the fuel at a constant consistency; but this variation in consistency of the fuel due to tcm erature changes may also be compensated for directly by making the needle valve 52 more readily expansible under increase in temperature, as is the intention in the construction shown in Figure l0, wherein the needle valve is shown supported by a tube 65. vIn this arrangement the needle valve will expand more rapidly under increase in temperature than its supporting tube 65, and thus reduce the port area at 51, as the fuel becomes thinned.

During the operation of the burner, the pump is continuously driven by motor 2. The motor shaft being connected with shaft 4 of the pump, the impellers 43 and 44, Figure 5, are operated to build up a pressure in chamber 57 and reduce the pressure in chamber 50.` The air before entering chamber 57 passes through the restriction or small port 15 which allows a partial vacuum to occur vnear the fuel orifice 51. The charged air then passes upwardly through the passageway 54 to the intake side of the compressor. The air is, therefore, charged with fuel before it reaches chamber 57. The more heavily charged air settles to the bottom of this chamber and passes through the outlet 17, Figure 6, and into conduit 12I Figure 1, leading to the burner. The more lightly charged air leaves the upper part of chamber 57 through the outlet 16, passing from there through conduits 8 and 9 tothe burner.

,The burner is thus supplied with two differently charged streams of air. The relative proportions of the air and fuel may, therefore, be regulated by an adJustment of the burner 10, whereby the outlets of conduits 9 and 12 are regulated.

Even though the gear pump supplies the chamber 48 `of the pump housing with fuel faster than it is picked up by the air traveling through passage-way 50, Figure 5, the excess fuel is merely re-circulatcd by being returned to the supply tank through conduit 7. Also, due to the constant speed of the motor, the volume of air delivered to chamber 57, Figure 5, may be greater than what is required by the burner. But all excess air without again passing the fuel supply orifice 51, is by-passed through the passage-way 63, 61 and 62 back to the intake conduit 54 of the air compressor. This occurs When the pressure in chamber 57 becomes high enough to lift the valve 58, Figure 8, from its seat.

I claim:

1. A fuel pump comprising a housing, a driven shaft journaled in said housing, an impeller secured to said shaft, a cooperating impeller anda supporting shaft therefor, also journaled in said housing, gears connecting saidshafts, and an inclosure for said gears-having an inlet for oil and means for discharging into said housing, said housing having an air inlet and an outlet.

2. A device of the .class described, comprising a housing having a chamber therein for receiving air and fuel, means for pumping air to said chamber and delivering fuel thereto in a jet `for carbureting the air, a

yprising a combustion device, means for pumping fuel andy airto said combustion device, said means Comprising a motor, a

shaft driven by the motor, an impeller fast to said shaft, a parallel shaft with a cooperv ating impeller fast therto, a housing for said impellers having an air inlet and an air outlet, gears for connecting said shafts for opposite rotation, and a housing for said gears having a fuel inl-et and a fuel outlet. y

Signed at Chicago this 11th 'day of May, 1923. GEORGE RAYMOND LAVRENCE. 

